This invention relates to ionomers. In one aspect, this invention relates to ionomers prepared from ethylene and an ionic functional comonomer while in another aspect, this invention relates to ionomers prepared from comonomers that form inverse micelles in ethylene or a hydrocarbon solvent under copolymerization conditions. In yet another aspect, this invention relates to the process of preparing and to the products made from these ionomers.
Ionomers and various methods for their preparation are known in the art. U.S. Pat. Nos. 4,248,990 and 4,252,924 to Pieski et al. and Chatterjee, respectively, teach a two-step process. In the first step, ethylene and an alpha, betaethylenically unsaturated carboxylic acid, e.g. (meth)acrylic acid, are copolymerized. In the second step, 5 to 90% of the ionized groups are neutralized with metal ions having an ionized valence of from 1 to 3 inclusive. The metal ions can be complexed or uncomplexed.
EPO application 86,115,591.1 by Herwig et al. teaches the manufacture of nonrandom ionomers by a one-step process in which the ionic functional comonomer is partially or fully neutralized prior to copolymerization with the ethylene monomer. The copolymerization is conducted in a homogeneous solution created through the action of a polar solvent, such as dimethylformamide, tetrahydrofuran, or an alcohol.